Biology

Photosynthesis in Plants

1,508 Questions

Photosynthesis is the biological process by which plants convert light energy into chemical energy. This page contains practice questions covering essential topics like chlorophyll, light reactions, and the pathways specific to plants. This material is crucial for medical entrance exams and academic assessments.

Chlorophyll and pigmentsLight reactionsCalvin cycleCAM plantsElectron transportPhotosynthesis factors

Photosynthesis in Plants Questions

Multiple choice

2-Carboxy-D-arabinitol 1-phosphate (CA1P) is synthesized by C4 plants like tobacco and beans in the night. Which of the following functions does it perform?

  1. Enhances the rate of photosynthesis

  2. Forms bonds with CO2 and helps in its storage

  3. Inhibits the catalytic activity of RuBisCo

  4. Incorporates more oxygen into RuBP
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

2-Carboxy-D-arabinitol 1-phosphate (CA1P) inhibits the catalytic activity of RuBisCo at night. RuBisCO activase promotes the release of CA1P from the catalytic sites.

Multiple choice

Which is known as an inhibitor of photosynthesis?

  1. Pyruvate reductase

  2. Glycolate oxidase

  3. 2-phosphoglycolate

  4. 3-phosphoglycerate
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Phosphoglycolate inhibits certain enzymes involved in photosynthetic carbon fixation. Hence, it is often said to be an 'inhibitor of photosynthesis'.

Multiple choice

Under which condition can C3 cycle not operate in plants?

  1. High CO2

  2. Absence of oxygen

  3. High CO2 and absence of oxygen

  4. Low CO2 and presence of oxygen
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

C3 cycle cannot operate under very low CO2 conditions and oxygen has inhibitory effect on photosynthesis. Thus, C3 cycle cannot operate in presence of oxygen.

Multiple choice

Why is enzyme triosephosphate isomerase required in the regeneration step of Calvin cycle?

  1. Conversion of a G3P and a DHAP into fructose 6-phosphate (6C)

  2. Conversion of all of the G3P reversibly into dihydroxyacetone phosphate

  3. Synthesis of erythrose-4-phosphate

  4. Cleavage of sedoheptulose-1,7-bisphosphate into sedoheptulose-7-phosphate
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Triosephosphate isomerase is required for conversion of all of the G3P reversibly into dihydroxyacetone phosphate (DHAP), which is a 3-carbon molecule.

Multiple choice

Which of the following statements is/are false: a. The organelles containing pigments present in the cytoplasm of plant cells are called plastids. b. The process of food making takes place in the chloroplasts. c. In the chloroplasts, oxygen and water combine in the presence of sunlight to form glucose.

  1. Only a

  2. Only a and b

  3. Only b

  4. Only b and c

  5. Only c
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Statement 'c' is a wrong statement. Thus, it is the correct option. In the chloroplasts, carbon dioxide and water combine in the presence of sunlight to form glucose.